For a multitude of different reasons, it is often times desirable to allow vehicle or work machines such as a wide variety of different types of earthmoving equipment to idle unattended. For example, in the case of work machines equipped with diesel engines, or other engines of a type which may be difficult to start, it is often times advantageous to keep these types of vehicles running at all times, even when such vehicles are left unattended. Also, earthmoving equipment typically operate in work environments which give rise to situations and/or conditions wherein the vehicle/work machine must be left unattended in an idle condition.
A wide variety of different types of theft deterrent systems are presently in use today on a wide variety of different types of vehicles in order to deter unauthorized use and/or theft of the vehicle. These theft deterrent systems are typically engaged through a wide variety of different activation means including activating such systems both when the particular vehicle goes through a normal engine shutdown procedure as well as while the vehicle engine remains running. The known theft deterrent systems typically include an alarm which emits a warning signal when unauthorized vehicle access is obtained, or such systems may include mechanical and/or electrical systems that inhibit the normal operation of the vehicle in some fashion.
In the case of the known theft deterrent systems which are engageable while the vehicle engine is still running, enablement of such systems are often times solely dependent upon monitoring only engine speed and/or vehicle speed. As a result, certain sensor failures and/or other engine operating conditions may allow such systems to be enabled under unsafe or less than desirable conditions. For example, machine operators have been known to unplug the vehicle speed sensor in order to bypass certain operational characteristics of the particular work machine involved. If this was to occur, or if the vehicle speed sensor was to fail, situations could arise wherein a secure idle mode of operation could be engaged while the work machine is actually moving or performing some type of work function. If such a theft deterrent system was to thereafter limit or alter normal vehicle operation, or even shutdown the engine, while the vehicle was still in motion, or while a particular work task or function was still being performed, an unsafe situation may occur.
Similarly, if the engine speed sensor was to fail, or was otherwise bypassed for some particular reason, a secure idle mode of operation could be enabled while the engine was actually performing work. Here again, this could give rise to an unsafe condition endangering the safety of both workers and equipment in the vicinity of the particular vehicle or work machine.
It is therefore desirable to provide an enhanced theft deterrent system for operating a vehicle in an unattended idle situation wherein a plurality of different operational state parameters including engine load parameters are monitored and evaluated prior to any enablement of such system, and wherein such system cannot be enabled if the engine is performing work, or is about to perform work, even if the vehicle speed and/or engine speed are within proper limits for enablement.
In addition, when a particular vehicle is being operated in the idle mode, it is often times desirable to run various parasitic loads while the vehicle is left unattended. Such parasitic loads may include operating heating and cooling fans, air conditioning, air compressors, and other such devices. When such parasitic devices are employed, engine RPM above low idle may be required. In some cases, such elevated engine speeds may exceed 2000 RPM. With the known prior art systems, such elevated engine speeds will trigger the theft deterrent features of such prior art systems, such as either shutting down the engine or limiting the operation of such engine to the idle mode. As a result, operation of certain parasitic loads when in a secure idle mode of operation is not possible.
Still further, in certain work environments, it may also be desirable to shutdown the vehicle engine after the vehicle has been left in an unattended idle condition for a predetermined period of time. Here again, the known theft deterrent systems operable to effect a secure idle mode of operation will not automatically shutdown the vehicle engine separate and apart from sensing and determining that a particular operational state parameter has not been maintained. While the known prior art systems are operable to provide at least some measure of vehicle theft protection in a secure idle mode of operation, such systems do not address the aforementioned problems and many such systems may be bypassed and/or defeated.
It is therefore also desirable to provide an enhanced theft deterrent system operable in a secure idle mode of operation wherein an elevated engine operation is achievable to run certain parasitic loads without triggering the theft deterrent features of the system. Under certain circumstances, it may also be desirable to have certain vehicle/engine events trigger a normal shutdown of the vehicle engine and enablement of other theft deterrent features. Still further, it is also desirable to monitor a wide variety of different vehicle/engine functions so as to defeat any attempt to bypass the system.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.